Ammunition for most firearms has a conventional construction. Generally, firearm ammunition consists of a cartridge which includes components that are consumed and components that must be ejected from the firearm. Conventional cartridges include a jacket or casing, a bullet seated in the casing, propellant contained within the casing behind the bullet, and a primer which ignites the propellant.
The casing is a cylindrical shell with an open front end and a closed rear end. The bullet may have many arrangements, but is often spherical, hemi-spherical, or somewhat conical in shape. The base of the bullet is seated into the front end of the casing, and the casing is crimped or otherwise sealed thereabout, thereby forming an interior of the cartridge. The propellant is carried within this interior. The propellant is a highly incendiary and combustive material; when it is ignited, very hot combustion gases are quickly formed and expand outwardly, causing the casing to expand outward and causing the bullet to burst forward. The primer controls the ignition of the propellant; the primer may be a pressure- or impact-sensitive chemical upon which a firing pin acts.
When a firing pin impacts the primer, the propellant combusts, and the bullet is sent hurtling out of the casing within the barrel of the firearm. The bullet exits the muzzle toward a target. The propellant and the primer are consumed during combustion. The casing, however, is not consumed and not jettisoned from the firearm. Rather, the casing is left expanded within the firing chamber. It must be cleared before a fresh cartridge can be fired.
The casing cools, and as it does, it contracts slightly. Cycling of the firearm will eject the casing. In some firearms, this is done manually by retracting the bolt so that the casing pops out of the ejection port. In other firearms, ejection occurs automatically as a feature of the operating system. With either method, the casing is cleared from the firing chamber so that a new cartridge may be introduced and shot.
Casings are conventionally made from brass, and as such, the community often refers to ejected casings as “spent brass.” Spent brass can be a hazard. First, it can get quite hot. As it is ejected, spent brass may drop in place or it may be launched a few inches to feet away, and bystanders hit by hot spent brass can be burned. Second, in an increasingly environmentally-minded world, it is irresponsible to allow spent brass to remain on the ground. A shooter may have quite a bit of spent brass, perhaps several hundred rounds. Leaving hundreds of used casings on the ground is not only unlawful littering, but damages the environment. However, it can be burdensome to pick up casings from the ground after ejection, and it certainly is no way to end an enjoyable shooting trip. One wants to simply set up, shoot, and then leave.
Brass catchers were developed to tackle the problem of spent brass. Conventional brass catchers are mesh nets or bags that can be attached to the top or side of the firearm. As a casing is ejected from the firearm, it enters the bag and is collected. However, a major problem with such brass catchers is the frequency with which they have to be emptied, and the interruption in shooting caused by the emptying. A shooter cannot fire hundreds of rounds nearly continuously; after twenty or thirty rounds, he has to pause, remove the brass catcher from the firearm, and dump its contents into a receptacle. This interrupts the shooting experience. Again, the shooter would most like to simply set up, shoot, and leave. An improved brass catcher which allows the shooter to shoot without interruption is needed.